Effect on mechanical properties of geopolymer concrete by addition of polypropylene fibers

Abstract

Geopolymer Concrete (GPC) is an innovative solution in construction industry which is manufactured to replace ordinary concrete. Ordinary concrete is considered as a major construction material around the globe, but cement involved in its production contributes about 5% of world’s total carbon dioxide emissions. GPC uses alternative materials such as Fly Ash (FLA), GGBS as a replacement for cement. These materials are waste by-products of thermal and coal industries and using those materials results in reduction of overall carbon footprint. However, research shows that overall embodied energy generated by GPC is greater than traditional concrete due to extensive use of elevated curing methodology. Alkaline Binder Solutions are used as a major binder material in the process. The research incorporated addition of Polypropylene Fibers (PF) into GPC because of its high tensile capacity and crack resistance ability. Further, the research investigated mechanical properties of GPC such as Compressive Strength (CS) and Flexural Strength (FS) through varying proportions of PF from 0 to 5%, by weight respectively. Simultaneously, the research also focused on physical properties of GPC like density. CS and FS were tested conforming to the requirements of IS: 516. Moreover, a Compression Testing Machine and an Automatic Flexural Testing Machine having respective capacities of 3000kN and 300kN were used for testing CS and FS. The research findings show the addition of fibers increases FS by 49% in M6 mix which contained 5% of polypropylene fibers. However, the CS of GPC was affected negatively by the addition of PF for M6 mix, it reduced to 46% in comparison to Mix M1 with 0% fibers. Physical properties of concrete such as density also got negatively affected by the inclusion of PF. At the end of the research, Mix M3 which contained 2% PF was found more reliable than other mix proportions.